100% RE by 2050 and the Effects of Lifetime and Recycling

Comparison case using the functions in PV ICE to compare how PV module lifetime and PV module recycling effect the energy transition to 100% clean energy by 2050.

Folder 15 vs 50 year Module

WORDS WORDS WORDS

File Preparation

First, we load the Module Baseline. Will be used later to populate all the columns other than 'new_InstalledCapacity[MW]' which will be supplied by the REEDS model. Unlike the SF simulations, this analysis will use PV ICE developed baselines.

NOTE: this section of code should only need to be run once to populate data, and again anytime the ReeDS file is updated.

Drop 1995 through 2009 because SF projections begin in 2010. Technically this neglects ~1.5 GW of installs from 1995 through 2009.

Now we load the ReEDS simulation output, i.e. the Solar Futures projections with PCA regions, States, and Scenarios. Note that this is stored outside of the PV ICE folder and therefore not publicly available on github

First create a copy which groups the data by PCA region

For each Scenario and for each PCA, combine with baseline and save as input file. This will be in a folder PCAs under the simulation folder in TEMP

For each Scenario and each State, combine with baseline file and save as input file. This will be in a folder States under the simulation folder in TEMP

Finally, make an overall US baseline which ignores PCA regions and states. This is useful for speeding the simulation.

Analysis

Collect all the scenario names and downselect to the scenario(s) of interest. In this case, we are only concerned with the highest capacity and deployment rate, Decarbonization + Electrification (Decarb+E)

Set up the PV ICE simulation with scenario and materials

Run the simulation

Lifetime and Recycling Scenario Creation

The range of potential future technology directions for PV will be explored in terms of module lifetime and EoL recycling rates. Currently technology is ~32 year module with a 6% EoL recycling rate (15% collection, 40% modules sent to recycling). Lifetimes could improve, with 50 years targeted by DOE SETO. And or recycling rates could improve, as modeled by CdTe management from First Solar or perovskite technology. This analysis will explore on a mass flow basis, which of these two circular economy levers is most important research priority for achieving the energy transition while minimizing waste and material extraction.

We will explore from a 15 year module lifetime to a 50 year module lifetime, and from 0% recycled to 100% recycled.

Create lifetime and recycling ranges

Now some magic to automatically generate T50 and T90 values for each lifetime

Create all Scenarios

Now with the lifetime and recycling ranges defined, create a scenario for each combination

Notes:

Use the PV ICE "aggregate results" function to print out a table of Virgin Material Demands, Lifecycle Wastes (MFG, EoL, both), new installed capacity and effective cumulative capacity, both annually and cumulatively.

Heat Map - Identical Installs

Read the aggregated results back into the journal from csvs (run time on simulations can be long)

Pie chart of Lifecycle Wastes in 2050, PV ICE scenario

Installation Compensation Calculation

NOTE: this mass flow calculation takes a LONG time to run, recommend leaving it overnight. A csv of the yearly and cumulative aggregated results is saved as csv and read back in to speed analysis and graphing.

Read the csvs back in for plotting (installation compensation calc runs a LONG time).

Bar chart of additional installations

Heat Map - Compensated Installs

Print out data for time shift bar charts, Fig 5

Sanity Check: BOM decrease and Efficiency increase

BOM modification

Approximating a "thin film" BOM as just glass, backsheet, an Aluminum Frame. This is similar to te CdTe modules.

Now calculate installation compensation for the 15 year module.

Search for the cumulative value that is less/more than the PV ICE baseline with all materials.

Here, we compare the PV ICE c-Si virgin material demand to a thin film of 15 year life. These results indicate that lowering the BOM will lower the required closed-loop recycling rate to reduce virgin material demands from 95% to 75%.

This compares the thin film BOM waste to the PV ICE c-Si baseline waste. The recyling requirement for lowering waste is still quite high. Given that most of the waste is attributable to pre-2020 low open-loop recycleable modules, little can be done about the pre 2050 waste.

Efficiency Modifcation

Now that we have confirmed that decreasing the mass per module area will lower the required closed-loop recycling rate, lets check that increasing module efficiency will have the same effect. Currently, PV ICE baseline is 20% efficiency in 2020 and 25% efficient in 2050. Oberbeck et al 2020 expect 30% efficient tandem devices (perovskite + silicon). Therefore, we will use this as an approximation of an efficiency increase, and will apply it to the 15 year module.

First we check the change in deployed capacity, since modifying module efficiency will primarily effect the deployment (and as a result effect virgin mateiral demand). Installs are only dependent on life, not recycling, therefore we can select any of the recycling rates.

Because we deploy using MW, the difference from efficiency improvement will not appear in MW deployed but in the area of those MW deployed. Therefore, we will compare the area deployed as a proxy for # of modules and compare the tandem 30% efficiency against the c-Si 25% efficiency 15 year modules, and PV ICE.

Area comparison

If we approximate a module as 2 m^2 (current average, though CdTe series 6 modules are 2.47 m^2), then we can use the area deployed to calculate an approximate number of modules.

This graph shows the cumulative deployed area over time for the PV ICE baseline, the "15-year Tandem" device, which is the same BOM but higher module efficiency (30%), and the c-Si 15 year module with the same efficiency as PV ICE (25%). We see that the higher efficiency lowers the required deployment area. Interestingly, around 2038, PV ICE and the 15-year Tandem device cross, because the replacement requirement for the 15-year Tandem is higher than PV ICE 35 year module. Cumulatively, the Tandem device still requires more area deployment. Next let's look at what level of closed-loop recycling will drop the virgin material requirements.

These results indicate that due to reduced area deployed, the necessary closed-loop recycling is lowered to 65%. This indicates that virgin material demand is more sensitive to module efficiency than BOM (which lowered the closed-loop recycling need to 75%).

Like the BOM change, lifecycle wastes are not as sensitive to module efficiency changes, since much waste is due to pre-2020 modules.

Breakthrough Technology: Thin Film + High Efficiency

Finally, what if there is breakthrough technology which is 30% efficient and a thin film technology (i.e. low BOM).

Now run capacity compensation. This is where the difference really lies, in how many fewer modules can be deployed due to increased module efficiency.

The reduction in area deployed should be identical to the module efficiency improvement analysis above. Therefore, we will just look at the combined effect on virigin material demand and the necessary closed-loop recycling rate.

The combined lower BOM and higher Efficiency reduce the required circularity to 50% closed-loop.

ALTERNATE BOM MODIFICATION

In this BOM modification, we will try to more accurately represent a thin film technology. Parameters will be identical glass baseline, Aluminum Frame, Backsheet, 10% of the c-Si, 50% of the encapsulant, and neglect Ag and Cu. The glass and backsheet baselines account for increasing shares of glass-glass packaging. Silicon absorber will be reduced to a thin film thickness as a proxy, and the encapsulant will be cut in half, since typically, thin film uses 1 sheet of encapsulant instead of the 2 sheets c-Si uses. This will include manufacturing inefficiencies of these materials. Current wafer thickness is ~165 micron, and CdTe thin films are 10s of microns; therefore we will use 10% of c-Si mass per area.

Now we analyze the results

These results indicate that 80% closed-loop recycling is required for this thin film BOM to extract fewer materials. This is an overall lowering of the BOM by:

This is ~12kg/m2. For reference, a CdTe series 6 module is ~14kg/m2